EP0155132B1 - Systèmes hydrauliques de freinage antiblocage pour véhicules - Google Patents

Systèmes hydrauliques de freinage antiblocage pour véhicules Download PDF

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Publication number
EP0155132B1
EP0155132B1 EP85301472A EP85301472A EP0155132B1 EP 0155132 B1 EP0155132 B1 EP 0155132B1 EP 85301472 A EP85301472 A EP 85301472A EP 85301472 A EP85301472 A EP 85301472A EP 0155132 B1 EP0155132 B1 EP 0155132B1
Authority
EP
European Patent Office
Prior art keywords
restrictor
brake
braking system
valve
pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP85301472A
Other languages
German (de)
English (en)
Other versions
EP0155132A3 (en
EP0155132A2 (fr
Inventor
David Charles Hurst
Alfred Yardley
Robert Alan Anderson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ZF International UK Ltd
Original Assignee
Lucas Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB848405903A external-priority patent/GB8405903D0/en
Application filed by Lucas Industries Ltd filed Critical Lucas Industries Ltd
Publication of EP0155132A2 publication Critical patent/EP0155132A2/fr
Publication of EP0155132A3 publication Critical patent/EP0155132A3/en
Application granted granted Critical
Publication of EP0155132B1 publication Critical patent/EP0155132B1/fr
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T11/00—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant
    • B60T11/10—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting by fluid means, e.g. hydraulic
    • B60T11/28—Valves specially adapted therefor
    • B60T11/30—Bleed valves for hydraulic brake systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
    • B60T8/4031—Pump units characterised by their construction or mounting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/42—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition having expanding chambers for controlling pressure, i.e. closed systems
    • B60T8/4208—Debooster systems
    • B60T8/4225—Debooster systems having a fluid actuated expansion unit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/50—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition having means for controlling the rate at which pressure is reapplied to or released from the brake
    • B60T8/5087—Pressure release using restrictions
    • B60T8/5093—Pressure release using restrictions in hydraulic brake systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/72—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration responsive to a difference between a speed condition, e.g. deceleration, and a fixed reference
    • B60T8/74—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration responsive to a difference between a speed condition, e.g. deceleration, and a fixed reference sensing a rate of change of velocity

Definitions

  • This invention relates to hydraulic anti-skid braking systems for vehicles of the kind set forth in which a supply of operating fluid from a supply to a vehicle brake is modulated by a modulator assembly in accordance with skid signals from skid sensing means, and a power source is incorporated to control brake reapplication following skid correction.
  • the modulator assembly comprises a bore in which works a de-boost piston for co-operation with a control valve assembly adapted to control communication between the supply of operating fluid and the brake through an expansion chamber defined in the bore between the piston and the control valve assembly.
  • a control valve assembly adapted to control communication between the supply of operating fluid and the brake through an expansion chamber defined in the bore between the piston and the control valve assembly.
  • a dump valve When a skid signal is produced a dump valve is operated so that the trapped volume of fluid is released which permits the piston to move into a retracted position, initially to permit the valve assembly to close and isolate the supply from the brake, and subsequently to increase further the effective volume of the expansion chamber, whereby to relieve the brake-applying pressure.
  • the pressure from a pump constituting the power source is operative to urge the piston towards its advanced position, initially to re-apply the brake by pressurising the fluid in the expansion chamber, and subsequently opening the valve assembly to re-establish communication between the supply and the brake.
  • the dump valve is movable between a fully open and a fully closed position to release the trapped volume of fluid, or to close the space so that fluid can become trapped therein again in order to permit the piston to return to its operative advanced position.
  • the pressure in the space is normally the same as the pressure applied to the brake.
  • the brake pressure can reach high levels, for example 103-124 bar (1500 - 1800 p.s.i.).
  • 103-124 bar (1500 - 1800 p.s.i.
  • the trapped volume of fluid is released so that brake pressure dives to a minimum. This is undesirable since difficulty may be experienced in re-applying the brakes at a desired pressure due to the capacity of the power source and in the necessarily limited time period.
  • GB-A-1386713 discloses an anti-skid braking system for a vehicle in which, at pressures above the threshold of a calibrated spring, pressure is released from a brake at a first rapid rate of release followed by a restricted release, and the restricted release, in turn, is followed by a further rapid release.
  • the modulator assembly comprises a bore in which works a de-boost piston for co-operation with a control valve assembly adapted to control communication between the supply of operating fluid and the brake, and the position of the de-boost piston is determined by a volume of fluid trapped in a space by a dump valve and provided by the power source, the dump valve is operative in response to a skid signal to release fluid from the brake at a first rate for pressures below a pre-set level, and restrictor means are incorporated for controlling the release of fluid from the brake at a second rate lower than the first rate for pressures above the pre-set level, the restrictor means comprising a pressure-responsive member operable in response to pressures above the pre-set level to bring into operation a restrictor operative to determine the second rate of fluid release, whereby upon operation of the dump valve fluid is released from the brake only at the second rate for all pressures above the pre-set level.
  • the provision of the restrictor means which decrease the dump flow rate at pressure, above the pre-set level thereby reduces the time period for each anti-skid cycle.
  • the power source no longer has to pressurise brake to maximum (brake) pressure from zero, but only from some intermediate pressure.
  • the rate at which pressure can be dumped from the brake can, with advantage, be increased in comparison with known dump valves which restrict to a lesser extent, the rate at which fluid is dumped, by increasing the area or capacity of the dump valve itself. This is of particular advantage when the vehicle is travelling over surfaces of lower co-efficient of friction since brake pressure can be released more rapidly than hitherto.
  • the restrictor may be adapted to restrict the release of fluid from the brake itself at pressures above the pre-set level ,when the dump valve is opened.
  • the restrictor may be arranged to restrict the release of fluid trapped in the said space by the dump valve at pressures above the pre-set level.
  • the output from the power source may be connected either to the upstream or the downstream side of the restrictor means.
  • the action of the restrictor means is independent of wheel speed velocity.
  • the restrictor means may be incorporated in the modulator assembly itself, or it may be separate from it and connected to it by an external connection.
  • the pressure-responsive member suitably a spool or piston, is movable in a bore to bring the restrictor into operation.
  • the pressure-responsive means comprises a spool
  • a land on the spool is biassed into a throat to define the restrictor which restricts the release of fluid from the brakes.
  • the piston is adapted to operate a valve member, which is movable in a direction to restrict the area of a passage or, alternatively, engage with a seating whereafter restricted flow takes place through a restricted passage through the seating or through the valve member itself.
  • the spool or the piston may work in a bore in a spool which is itself manually displaceable in a bore in the housing against the spring loading the de-boost piston into its advanced position, in order to affect bleeding of the system.
  • the assembly illustrated in the drawing comprises a housing 1 incorporating a modulator assembly 2, a hydraulic pump assembly 3, and a pressure dump valve 4.
  • a longitudinally extending shaft 5 projecting at opposite ends through the housing 1 is coupled at one end to a wheel to be braked and at the other end carries skid sensing means 6 which is enclosed within a cylindrical guard 6a carried from an adjacent end of the housing.
  • the dump valve 4 and the skid sensing means 6 may be of any of the forms disclosed in GB-A-2029914, and the pump assembly 3 forms the subject of GB-A-2069640. These latter mechanisms need not be described further herein except to mention that the pump 3 is urged in one direction by an eccentric 5a on the shaft 5 and in the opposite direction by pressure from the master cylinder acting over an operating piston 3a. The area or capacity of the dump valve 4 is increased and the dump valve 4 operates in conjunction with a restrictor 40 which will be described later.
  • the modulator assembly 2 comprises a bore 8 extending from the dump valve 4 and in which works a de-boost piston 9.
  • the piston 9 is normally urged into an inoperative position against a stop comprising a wall 10 at the closed end of a sleeve 11 substantially of cup-shaped outline by means of a spring 12, and the sleeve 11 is retained in the bore 8 by means of a closure 13 for the end of the bore 8 remote from the dump valve 4.
  • a control valve assembly 14 housed in the sleeve 11 controls communication between a pedal-operated master cylinder 15 and a wheel brake 16 through an expansion chamber 17 defined in the bore 8 between the piston 9 and the control valve assembly 14.
  • the control valve assembly 14 comprises a first valve 18, and a second valve 19 which are operative sequentially.
  • the first valve 18 comprises a first valve member 20 in the form of a stepped piston having a portion of intermediate diameter working in the bore of the sleeve 11, an outer portion of largest diameter working in a blind bore 21 of the closure 13, an inner portion of smaller diameter carrying an annular seal 22 which defines a valve head, and an innermost portion of smallest diameter which projects into a circular opening 23 in the wall 10.
  • the valve head 22 is engageable with a seating 24 comprising an annulus oh the wall 10 which surrounds the opening. Normally the head 22 is spaced from the seating 24 by means of a spring 25 which acts between the wall 10 and a shoulder 26 at the step in diameter between the intermediate and the smaller diameter portions of the piston 20.
  • the piston 20 has an open-ended longitudinally extending bore 27 of stepped outline in which the second valve 19 is housed.
  • the second valve 19 comprises a valve member 28 in the form of a ball which is engageable with a seating 29 defined by a shoulder at the step in diameter of the bore 27.
  • the ball 28 is normally urged away from the seating 29 by a probe 30 with which the piston 9 co-operates against the force in a light compression spring 31.
  • the dump valve 4 In the normal inoperative position shown in the drawing the dump valve 4 is closed to isolate the support chamber 50 in the portion of the bore 8 above the piston 9 from a reservoir 32 for fluid.
  • the piston 9 is therefore held in an inoperative advanced position in which the second valve 19 is held open by the probe 30, and the first valve is held open by the spring 25.
  • hydraulic fluid is supplied to the brake 16 through radial ports 33 in the wall of the sleeve 11, and through the open first valve 18 to the expansion chamber 17. Simultaneously fluid also enters the through-bore 27 through a port 32 in the wall of the piston 20 and can pass to the expansion chamber 17 through the open second valve 19. Thus there is a substantially unrestricted flow of fluid to the brake.
  • Fluid from the master cylinder acts on the shoulder 26 at the step in diameter, over the valve head 22, and over the outer end of the piston 20 which is of greatest area.
  • the unrestricted communication continues until the pressure from the master cylinder attains a predetermined value such that the force acting on the piston 20 due to the pressure acting over the end of greatest area overcomes the force in the spring 25 plus the force due to that pressure acting over the shoulder 26 and the head 22.
  • the first valve 18 then closes, and any further pressure increase can only take place at a reduced rate by flow through a restricted path comprising the clearance between the valve member 28 and the seating 29.
  • the skid sensing means 6 When a skid signal is received the skid sensing means 6 is operative to open the dump valve 4 which releases the volume of fluid trapped in the chamber 50 of the bore 8 so that the piston 9 can retract against the force in the spring 12 initially to allow the second valve 19 to close since the pressure at which a skid signal can be emitted is higher than that at which the first valve 18 will have closed.
  • Opening the dump valve 4 also unbalances the pump 3 causing it to pump fluid in a closed circuit into the chamber 50 from the reservoir 32 to which it is returned, through the open dump valve 4. Since communication between the piston 3a and the master cylinder 15 is unrestricted, the pump 3 can move freely.
  • the dump valve 4 closes to isolate the bore 8 from the reservoir 32 and the pump 3 is then operative to increase the pressure in the chamber 50, with the result that the piston 9 is urged towards its inoperative, advanced, position.
  • Initial movement of the piston 9 in this direction re-applies the brake 16 by pressurising the volume of fluid trapped in the expansion chamber 17, and subsequent movement opens the second valve 19 to establish a restricted flow from the master cylinder to the expansion chamber 17 through the clearance between the ball 28 and the seating 29.
  • the first valve 18 closes at a predetermined pressure independent of the movement of the piston 9.
  • the second valve 19 is closed and opened by movement of the piston 9 away from and towards its stop 10 on the sleeve 11.
  • the first valve 18 re-opens to provide a free and unrestricted communication between the master cylinder 15 and the brake 16.
  • the dump valve 4 operates in conjunction with the restrictor 40 shown in detail in Figures 3 and 4 of the drawings, and the restrictor 40 is combined with a bleed device 41.
  • an outer spool 42 works in a stepped bore 43 in the housing 1 and carries three axially spaced seals 44, 45 and 46a in three portion of progressively increased diameters.
  • the seals 44 and 46 seals at all times with the corresponding portions of the bore 43, and the seal 45 is movable between the position shown in which it seals against the intermediate portion of the bore to isolate a passage 46 leading to the pump 3 from a passage 47 to atmosphere, and a position within the portion of the bore 43 which is a greatest diameter in order to place the two passages 46 and 47 in communication.
  • the spool 42 is urged into the position shown by the spring 12.
  • the spool 42 has an axial through-bore 48 terminating at its inner end in a throat 49 of frusto-conical outline of which the diameter increases towards a space 50 within the bore 8.
  • An inner spool 51 works through the bore 48 and at its outer end works through a seal 52 received in a recess 53 at the outer end of the outer spool 42.
  • the spool 51 incorporates spaced lands 54 and 55 of which the land 54 is guided in the bore 48 at all times.
  • a spring 56 acts between the inner ends of the two spools 42 and 51 normally to urge the inner spool 51 in a direction in which the land 55 is spaced from the outer end of the throat 49. This provides unrestricted communication between the space 50 and the passage 46 leading to the dump valve 4.
  • the dump valve 4 Under normal braking, the dump valve 4 is closed and maintains the volume of support fluid in the space 50 to hold the piston 9 in its advanced position.
  • the pressure in the space 50 is the same as that applied to the brake.
  • the brake pressure can reach high levels, e.g. 103-124 bar (1500 - 1800 p.s.i.).
  • the fluid would be released from the space 50 so that the pressure would dive to the minimum.
  • the decreased dump flow rate therefore reduces the time period for each anti-skid cycle, and the pump 3 no longer has to pressurise back to a maximum (brake) pressure from zero but only from some intermediate pressure e.g. 34 bar (500 p.s.i.).
  • the spool 42 is displaced axially in the bore 43 by a manual force applied to its outer end against the load in the spring 12, and the seal 45 disengages from the intermediate portion of the bore 43.
  • the two passages 46 and 47, and chamber 50 are thus placed in communication for bleeding to take place.
  • spool 51 has been replaced by a pressure reaction piston 60 which works in the bore 48 of the outer spool 42.
  • a spring 61 acts on the piston 60 normally to bias it in a direction to urge a valve member 62 in the form of a ball away from a seating 63 at a step in diameter of the bore 48 between bore portions 68 and 69.
  • a light spring 64 acts to bias the ball 62 at all times against a probe 65 projecting forwardly from the piston 60.
  • a restricted orifice 66 in the spool 42 provides restricted communication between the chamber 50 and the passage 46 when the ball 62 is in communication with the seating 63.
  • the restrictor 40 is separate from the housing 1 and is located in the line between the expansion chamber 17 and the brake.
  • the restrictor 40 comprises a housing 70 provided with a longitudinally extending stepped blind bore 71 which is closed at its inner end of smallest diameter.
  • the bore 71 has three portions of smallest, intermediate and greatest diameters 72, 73, 74.
  • the outer end of the portion 74 of greatest diameter is connected to the brake, and a radial port 75 in the wall of the housing 70 and leading into the bore portion 73 is connected to the chamber 17.
  • a piston 76 working in the bore portion 73 is radially biassed by a spring 77 in a direction to hold a valve member in the form of a ball 78 away from a seating 79 at the step in diameter, between the bore portions 73 and 74.
  • the bore portion 71 at the inner end of the piston 76 is connected to a reservoir 80 to collect fluid which may leak past a seal 81 at the inner end of the piston 76 and received in a groove at the inner end of a probe 82 through which the piston acts on the ball 78.
  • a restricted orifice 83 provides a limited flow between the brake 16 and the chamber 17.
  • the modulator assembly illustrated in Figure 10 of the drawings shows a modification of the restrictor 40 of Figure 8, in which the output from the pump 3 is connected to the downstream side of the restrictor 40 through a passage 85 and not through the chamber 50.
  • the action of the restrictor 40 does not depend upon wheel speed velocity.
  • FIG. 11 of the drawings A layout of a further anti-skid braking system is shown in Figure 11 of the drawings.
  • a wheel brake 101 is adapted to be applied by a pedal-operated master cylinder 102 through a modulator assembly 103 which is responsive to skid signals from a sensor 104 for sensing the speed of rotation of the wheel braked by brake 101.
  • the modulator assembly 103 comprises a housing 105 having a stepped longitudinally extending bore 106 in which works a stepped de-boost piston 107, an expander chamber 108 defined in the bore 106 between the end of the piston 107 which is of smaller area and a first valve 109 for controlling communication from the master cylinder 102 to the brake 1 through the expander chamber 108, and a support chamber 110 defined in the bore 106 between the opposite end of the piston 107 and a solenoid-operated valve 111 which communicates with the support chamber 110 through a restrictor valve 100.
  • the solenoid operated valve 111 is controlled by electrical signals from an electronic control module 112, in turn responsive to signals from the sensor.
  • the system is provided with a power source constituted by an accumulator 118 which is charged by a pump 120 which, in turn, draws fluid from a reservoir 114 which is separate from the pump 120.
  • Fluid from the accumulator 118 is supplied to the support chamber 111 through a flow-control regulating valve 119 comprising a spool 121 which works in a bore 122 in the piston 107 and is provided with a blind bore 123 terminating at its inner end adjacent to the support chamber 110 in a fixed orifice 124.
  • a diametrical passage 125 traverses the bore 123 and its outer ends lead into an annular groove 126 which co-operates with a radial port 127 leading from the accumulator 118 to constitute a variable restrictor.
  • the spool 121 is held by a spring 128 in a position of maximum flow.
  • a ball comprising a valve member 141 is held away from a seating 142 by an axially extending stem 143 which slides through the piston 107.
  • the valve member 141 and the seating 142 constitute the valve 109.
  • the restrictor valve 100 comprises a piston 130 working in a bore 131 and normally urged by a spring 132 in a direction to hold an enlarged head 133 away from a seating 134.
  • the seating 134 comprises a shoulder in the housing 105 at the inner end of the bore 131.
  • the head 133 is provided with a restricted orifice 134 which provides a limited flow through the head 133 when the head 133 is in engagement with the seating 134.
  • valve 111 In the position shown in the drawing the valve 111 is closed and the valve 109 is open to allow the brake 101 to be applied normally from the master cylinder and with the de-boost piston 107 held in the advanced position by equal pressures from the accumulator 118 acting over portions of the piston 107 of different areas at opposite ends of the orifice 124, with the pressure from the actuator being supplied through the flow control regulating valve 119, to the chamber 110.
  • the solenoid-operated valve 111 opens to place the support chamber 110 in communication with the reservoir 114. Due to a pressure drop across the fixed orifice 124, the spool 121 moves rapidly away from its retracted position, to cause the valve member 141 to engage with the seating 142 and isolate the master cylinder 102 from the. brake 101.
  • the loss of pressure in the support chamber 110 permits the de-boost piston 107 to retract, thereby relieving the brake-applying pressure.
  • valve 111 closes to isolate the support chamber 110 from the reservoir 114 and fluid from the accumulator 118 returns the de-boost piston 107 at a rate determined by the flow-control regulating valve 119 in accordance with the pressure drop across the orifice 124 and the load in the spring 128, to force the piston 107 to return the advanced position and re-apply the brake 101.
  • the valve member 141 remains in engagement with the seating 142 since the spool 121 is still in the advanced position.
  • the flow through the flow-control regulating valve 119 is determined by the force in the spring 128 and this force, divided by the area of the spool 121, determines the pressure drop across the orifice 124.

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Regulating Braking Force (AREA)

Claims (14)

1. Système hydraulique de freinage antipati- nage pour véhicules, dans lequel une arrivée de fluide de commande, en provenance d'une source (15), dans un frein (16) de véhicule est modulée par un ensemble modulateur (2) en fonction de signaux de patinage provenant de moyens (6) de détection du patinage, et une source d'énergie (3) est incorporée pour commander la réapplication du frein à la suite d'une correction pour patinage, dans lequel l'ensemble modulateur comporte un alésage (8) dans lequel travaille un piston (9) de réduction de la pression pour coopérer avec un ensemble (14) de distribution et de régulation conçu pour commander la communication entre la source de fluide de commande et le frein, et dans lequel la position du piston de réduction de la pression est déterminée par un volume de fluide piégé dans un espace (50) par une soupape de décharge (4) et fourni par la source d'énergie, caractérisé en ce que la soupape de décharge (4) opère en réponse à un signal de patinage pour laisser s'évacuer le fluide hors du frein (16) à un premier débit pour des pressions inférieures à un niveau prédéterminé et en ce que des moyens (40) de restriction sont incorporés pour commander l'évacuation du fluide hors du frein (16) à un second débit inférieur au premier débit pour les pressions supérieures au niveau prédéterminé, les moyens (40) de restriction comportant un organe (51, 60, 76, 131), sensible à la pression, qui peut opérer en réponse à des pressions supérieures au niveau prédéterminé, pour mettre en service un organe (49, 62, 6, 83, 134) de restriction servant à déterminer le second débit dévacuation du fluide, ce par quoi, lorsque la soupape de décharge (4) opère, le fluide n'est évacué hors du frein qu'au second débit pour toutes les pressions supérieures au niveau prédéterminé.
2. Système de freinage selon la revendication 1, caractérisé en ce que l'organe de restriction est conçu pour restreindre l'évacuation du fluide hors du frein (16) lui-même aux pressions supérieures au niveau prédéterminé, lorsque la soupape de décharge (4) est ouverte.
3. Système de freinage selon la revendication 1, caractérisé en ce que l'organe de restriction est agencé pour restreindre l'évacuation du fluide piégé dans ledit espace (50) par la soupape de décharge (4) aux pressions supérieures au niveau prédéterminé.
4. Système de freinage selon la revendication 3, caractérisé en ce que la sortie de la source d'énergie (3) est reliée au côté amont des moyens (40) de restriction.
5. Système de freinage selon la revendication 3, caractérisé en ce que la sortie de la source d'énergie est reliée au côté aval des moyens (40) de restriction par l'intermédiaire de (85).
6. Système de freinage selon l'une quelconque des revendications précédentes, caractérisé en ce que le moyen (40) de restriction est incorporé dans l'ensemble modulateur (2) lui-même.
7. Système de freinage selon l'une quelconque des revendications 1-5, caractérisé en ce que le moyen (40) de restriction est distinct de l'ensemble modulateur (2) lui-même et lui est relié par une liaison extérieure (75).
8. Système de freinage selon l'une quelconque des revendications précédentes, caractérisé en ce que l'organe (51, 60, 76, 130), sensible à la pression, peut se déplacer dans un alésage (48, 68, 71, 131) pour mettre en service l'organe (49, 62, 6, 83, 134) de restriction.
9. Système de freinage selon la revendication 8, caractérisé en ce que l'organe sensible à la pression comporte un tiroir (5) qui est normalement contraint, par un ressort, jusque dans une position ouverte dans laquelle une saillie (55) est normalement espacée d'un goulot (49) prévu dans l'alésage (48) dans lequel le tiroir est guidé pour glisser, une augmentation de pression, dans cet espace, l'amenant à une valeur prédéterminée poussant la saillie dans le goulot en agissant contre la force de la contrainte par le ressort pour définir la restriction qui restreint l'évacuation du fluide hors de l'espace.
10. Système de freinage selon la revendication 8, caractérisé en ce que l'organe sensible à la pression comporte un piston (60, 76, 130) qui est normalement contraint, par un ressort, dans un premier sens pour maintenir un organe formant soupape (28, 62, 133) en position ouverte, le piston pouvant se déplacer dans le sens opposé, en réponse à une augmentation de pression, pour permettre à l'organe formant soupape de se déplacer jusque dans une position fermée, et l'organe (62, 66, 83, 134) de restriction étant prévu pour permettre un écoulement réduit au-delà de l'organe formant soupape lorsque l'organe formant soupape est en position fermée.
11. Système de freinage selon la revendication 10, caractérisé en ce que l'organe de restriction comporte un passage réduit (66, 83) de part et d'autre d'un siège (63, 79) avec lequel l'organe formant soupape (62, 133) peut venir en contact en position fermée.
12. Système de freinage selon la revendication 10, caractérisé en ce que l'organe de restriction comporte un passage réduit (134) à travers l'organe formant soupape (133).
13. Système de freinage selon la revendication 10, dans lequel l'organe de restriction est défini par un jeu autour de l'organe formant soupape (62) lorsque l'organe formant soupape se trouve en position fermée.
14. Système de freinage selon l'une quelconque des revendications 8-13, caractérisé en ce que l'organe sensible à la pression travaille dans un alésage (43) prévu dans un tiroir (42) que l'on peut lui-même déplacer manuellement dans un alésage prévu dans le boîtier, en agissant contre le ressort (12) qui contraint le piston de réduction de la pression, pour l'amener dans sa position avancée pour effectuer la purge du système.
EP85301472A 1984-03-07 1985-03-04 Systèmes hydrauliques de freinage antiblocage pour véhicules Expired EP0155132B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB8405903 1984-03-07
GB848405903A GB8405903D0 (en) 1984-03-07 1984-03-07 Hydraulic anti-skid braking systems for vehicles
GB8416801 1984-07-02
GB848416801A GB8416801D0 (en) 1984-03-07 1984-07-02 Hydraulic anti-skid braking

Publications (3)

Publication Number Publication Date
EP0155132A2 EP0155132A2 (fr) 1985-09-18
EP0155132A3 EP0155132A3 (en) 1986-08-13
EP0155132B1 true EP0155132B1 (fr) 1989-05-31

Family

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Application Number Title Priority Date Filing Date
EP85301472A Expired EP0155132B1 (fr) 1984-03-07 1985-03-04 Systèmes hydrauliques de freinage antiblocage pour véhicules

Country Status (11)

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US (1) US4721346A (fr)
EP (1) EP0155132B1 (fr)
AU (1) AU577829B2 (fr)
BR (1) BR8501006A (fr)
CS (1) CS261879B2 (fr)
DE (1) DE3570631D1 (fr)
ES (1) ES8609076A1 (fr)
GB (1) GB2155573B (fr)
PT (1) PT80056B (fr)
SU (1) SU1449003A3 (fr)
TR (1) TR22218A (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3565079D1 (en) * 1984-03-07 1988-10-27 Lucas Ind Plc Improvements in hydraulic anti-skid braking systems for vehicles
US4648664A (en) * 1984-03-07 1987-03-10 Lucas Industries Public Limited Company Hydraulic anti-skid braking systems for vehicles
GB8507620D0 (en) * 1985-03-23 1985-05-01 Lucas Ind Plc Braking systems
DE3537127A1 (de) * 1985-10-18 1987-04-23 Bosch Gmbh Robert Blockierschutzbremsanlage
DE4027848A1 (de) * 1990-09-03 1992-03-05 Teves Gmbh Alfred Kolbenpumpe
US6957872B2 (en) * 2004-01-28 2005-10-25 Delphi Technologies, Inc. Integrated pre-charge for controlled brake systems
DE102012213216A1 (de) * 2011-08-15 2013-02-21 Continental Teves Ag & Co. Ohg Bremsbetätigungseinheit

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GB1386713A (en) * 1972-02-10 1975-03-12 Fiat Spa Antiskid braking system
EP0154542A2 (fr) * 1984-03-07 1985-09-11 LUCAS INDUSTRIES public limited company Dispositif d'anti-blocage pour systèmes hydrauliques de freinage pour véhicules
EP0154541A2 (fr) * 1984-03-07 1985-09-11 LUCAS INDUSTRIES public limited company Dispositif d'anti-blocage pour systèmes hydrauliques de freinage pour véhicules

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CA936149A (en) * 1970-02-28 1973-10-30 Girling Limited Control valves for hydraulic fluids
GB1295424A (fr) * 1970-06-26 1972-11-08
GB1435536A (en) * 1973-06-16 1976-05-12 Girling Ltd Hydraulic braking systems
GB2027832B (en) * 1978-08-18 1982-09-08 Lucas Industries Ltd Rotary flywheel skid sensing means for vehicle hydraulic braking systems
GB2109492B (en) * 1978-08-18 1983-10-05 Lucas Industries Ltd Improvements in hydraulic anti-skid braking systems for vehicles
GB2069640B (en) * 1980-02-16 1983-12-07 Lucas Industries Ltd Hydraulic anti-skid braking systems for vehicles
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US4436348A (en) * 1981-10-13 1984-03-13 Lucas Industries Public Limited Company Anti-skid hydraulic braking systems for vehicles
GB2109069B (en) * 1981-11-09 1985-08-07 Lucas Industries Ltd Modulators in hydraulic anti-skid braking systems for vehicles

Patent Citations (3)

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Publication number Priority date Publication date Assignee Title
GB1386713A (en) * 1972-02-10 1975-03-12 Fiat Spa Antiskid braking system
EP0154542A2 (fr) * 1984-03-07 1985-09-11 LUCAS INDUSTRIES public limited company Dispositif d'anti-blocage pour systèmes hydrauliques de freinage pour véhicules
EP0154541A2 (fr) * 1984-03-07 1985-09-11 LUCAS INDUSTRIES public limited company Dispositif d'anti-blocage pour systèmes hydrauliques de freinage pour véhicules

Also Published As

Publication number Publication date
PT80056B (en) 1986-10-20
ES540991A0 (es) 1986-04-01
CS261879B2 (en) 1989-02-10
PT80056A (en) 1985-04-01
BR8501006A (pt) 1985-10-29
EP0155132A3 (en) 1986-08-13
GB2155573B (en) 1987-12-09
AU577829B2 (en) 1988-10-06
CS159385A2 (en) 1988-07-15
ES8609076A1 (es) 1986-04-01
AU3914885A (en) 1985-09-12
GB8505571D0 (en) 1985-04-03
DE3570631D1 (en) 1989-07-06
GB2155573A (en) 1985-09-25
US4721346A (en) 1988-01-26
TR22218A (tr) 1986-10-06
EP0155132A2 (fr) 1985-09-18
SU1449003A3 (ru) 1988-12-30

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